// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_CHILD_CHILD_HISTOGRAM_MESSAGE_FILTER_H_
#define CONTENT_CHILD_CHILD_HISTOGRAM_MESSAGE_FILTER_H_

#include <memory>
#include <string>
#include <vector>

#include "base/macros.h"
#include "base/memory/shared_memory.h"
#include "ipc/message_filter.h"

namespace base {
class HistogramDeltaSerialization;
class SingleThreadTaskRunner;
} // namespace base

namespace content {

class ChildHistogramMessageFilter : public IPC::MessageFilter {
public:
    ChildHistogramMessageFilter();

    // IPC::MessageFilter implementation.
    void OnFilterAdded(IPC::Channel* channel) override;
    void OnFilterRemoved() override;
    bool OnMessageReceived(const IPC::Message& message) override;

private:
    typedef std::vector<std::string> HistogramPickledList;

    ~ChildHistogramMessageFilter() override;

    // Message handlers.
    void OnSetHistogramMemory(const base::SharedMemoryHandle& memory_handle,
        int memory_size);
    void OnGetChildHistogramData(int sequence_number);

    // Extract snapshot data and then send it off to the Browser process.
    // Send only a delta to what we have already sent.
    void UploadAllHistograms(int sequence_number);

    IPC::Sender* sender_;

    scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;

    // Prepares histogram deltas for transmission.
    std::unique_ptr<base::HistogramDeltaSerialization>
        histogram_delta_serialization_;

    DISALLOW_COPY_AND_ASSIGN(ChildHistogramMessageFilter);
};

} // namespace content

#endif // CONTENT_CHILD_CHILD_HISTOGRAM_MESSAGE_FILTER_H_
